metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: White to pale pink/beige; Luster: Vitreous to dull; Crystal structure: Trigonal (granular texture); Cleavage: None/Conchoidal fracture.
- Hardness
- 7 on Mohs scale
- Color
- White to pale pink/beige
- Luster
- Vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: White to pale pink/beige; Luster: Vitreous to dull; Crystal structure: Trigonal (granular texture); Cleavage: None/Conchoidal fracture.
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under intense heat and pressure, typically during mountain-building events. Geological age varies by location, often Precambrian to Paleozoic.
Uses & applications
Used in construction as crushed stone for roadbeds or railway ballast, as dimension stone for wall coverings and flooring, and occasionally in glassmaking if pure.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks in mountainous areas, forming prominent ridges and peaks. It is distinguished from sandstone by the fact that it breaks through the quartz grains rather than around them.
Field identification & locations
Identify in the field by its extreme hardness (cannot be scratched by steel) and lack of reaction to acid. It is commonly found in metamorphic belts worldwide, such as the Appalachians or the Alps.
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